Hmm. Well, yeah, this is a nit. But unfortunately its an intentional nit. In that its behaving exactly as it was designed, but obviously the appropriate usage isnt obvious enough. So for instance the text remains so you can easily send the message several times. Likewise MOVE/SEND etc all do the same thing, because you can send and delete at the same time.

The way to deselect sending is to click on "Don't send at all".

The way to avoid the issue entirely is to mark the message for at the same time you send your response.

Perhaps SiteDocClan needs to write up a nice how-to guide or something.